Valve facing means



Sept. 7, 1937. E. A. HALL VALVE FACING MEANS Filed Oct. 14, 1936 SYVUQ/HM [mesf A. Ha// Patented Sept. 7, 1937 UNITED STATES VALVE FACING MEANS Ernest A. Hall, Toledo, Ohio, assignor to The Hall Manufacturing Company, Toledo, Ohio, .a

corporation of Ohio Application October 14, 1936, Serial No. 105,506

3 Claims.

-This invention relates to means for facing valve heads particularly of the poppet valve type.

In the use of machines of this character, the grinding or facing wheel is driven at a high surface speed of approximately 6000 feet per minute and the valve head is driven at a very much lower surface speed. It is found in practice that in order to effect satisfactory grinding and to prevent chattering, which leaves a rough or what is termed a chatter surface on the valve face, it is necessary to change the valve head speed to suit not only the diameter of the valve but the degree of hardness of the valve surface and the material composing such surface. With respect to the valve head diameter, it is apparent that if one valve head having a diameter of 1" and another valve head having a diameter of 3 are driven at the same speed, there will be'a material difference in their surface speeds, that of one being 39 and of the other 137 feet per minute. It is found that this speed difference materially affects the grinding efficiency. As to the valve material, it is found that so far as speed requirements are concerned, cast iron is entirely different from soft steel, and that soft steel is different from hard steel. Valves of various materials and hardness are used, and it is now common, particularly for heavy duty work, to give valves a very hard surface for facing them with a material known as Stellite.

It is also found in the use of valve face grinding machines that as wear occurs in the bearing parts in use imperfections in grinding such as' chattered surfaces are more noticeable and thus become more objectionable. This is not so apparent on small diameter valves, or those having soft surfaces, but when facing large diameter valves, or those with hard surfaces, the valves have a tendency to climb onto the grinding wheel instead of allowing the wheel to cut itself free. By slowing down the valve to the proper speed, this tendency is overcome.

It is further found that where the valve and grinding wheel are driven from the same motor and reduction gearing is used to vary the speed of driving of the valve, the valve will have a chatter finish-a fine ridge appearing on the faced surface for each tooth of a certain gear of the reduction set-thus making the use of gearing for such purposes objectionable.

The object of the present invention is the provision in a valve facing machine having separate sources of power for the grinding wheel and valve, of electric means for varying the speed of driving of the valve a desired extent independently of the speed of the grinding wheel to obtain proper working conditions to suit the diameter of a valve and the kind and hardness of its material. r

The invention is fully described in the following specification, and one embodiment thereof illustrated in the accompanying drawing, in which Figure l is a plan view of a valve facing ma- 10 chine embodying the invention; Fig. 2 is a fragmentary elevation of the valve driving unit of the machine taken in the direction of the arrow in Fig. 1, a part being broken away and the electric wiring being diagrammatically shown, 15 and Fig. 3 is a section of the machine on the line 3-3 in Fig. 1.

Referring to the drawing, I designates a machine frame or, face, on the top of which is mounted at one end a grinding wheel driving 20 and carrying unit A and at its other end a valve driving and carrying unit B with the axes of the grinding wheel and valve disposed in interi secting angular relation, as is common in machines of this character.

The grinding wheel 2 is carried by a shaft 3 for both rotary and axial adjusting movements in the frame part 4 of unit A. The driving of the shaft 3 is effected from an electric motor 5 mounted within the frame I below the. unit 30 A and having belt and pulley driving connection with the shaft 3. An axial adjustment of the shaft 3 is effected by a turning of the hand wheel 6 which has its shaft in rack and pinion engagement with the carrying means for the 35 shaft 3, as well understood in the art.

The valve ID to be faced has its stem mounted in a drive chuck l I, the shaft of which is mounted in a bearing head l2 and carries a worm wheel l3 (Fig. 2) in mesh with a drive 40 worm M on the shaft l5 of an electric motor IS. The bearing head 12 and motor l6 are adjustable in a plane at right angles to the axis of the valve 10 by an adjusting means which is controlled by a turning of the handle H, as well un- 45 derstood in the art. The details of construction of the two units A and B and their manner of adjustment are well understood in the art and form no part of the present invention, and are, therefore, not specifically shown and described. 50

In order to provide a variable speed drive for the valve l0, one of the lead wires I8 of the motor 16 has a rheostat switch [9 disposed therein, so that the resistance in the current supply line to the motor may be varied at the will of 55 by using a worm wheel drive [3,

the operator to suit the speed of driving desired for the material and size of the valve being faced. It is found in practice that if spur gears are employed to transmit power from the motor or driving source IE to the valve ID, a slight chatter ridge will occur on the valve face for each tooth of one of the gears of the power transmission means, and that this chatter action is avoided l4 between the motor shaft and valve.

In operation, the relative adjustment of the grinding wheel 2 andvalve Ill to place them in proper facing relation is the same as in machines now commonly used for this purpose. The only difference in the present machine over those heretofore used is the provision of an electric motor drive for the valve l0,'which is entirely separate and independent of the driving means for the grinding wheel, connecting the drive motor to the valve carrying spindle in a manner to impart a smooth driving action, such for instance as through a worm and worm wheel production gearing, and interposing an electric resistance control in the circuit for the motor l6,

so that the speed of driving of the valve may be varied through a change in the driving speed of the motor rather than in a change of the power connection .between'the motor and valve carrying spindle. This enables an operator to change in a simple manner the speed of driving of the valve being faced so as to give most efiicient results, taking into consideration the diameter of the valve head and the material of which it is composed.

I wish it understood that my invention is not limited to any specific construction, arrangement or form of the parts, as it is capable of numerous modifications and changes without departing from the spirit of the claims.

Having thus described my invention, what I claim as new, and desire to secure by United States Letters Patent, is: I

1. A valve facing machine, including a rotatable grinding means, power means for actuating said grinding means at a predetermined constant speed, a rotatable work carrying spindle posi-- constant speed of the grinding means at the will of the operator dependent upon the known character and size of the material being ground.

2. A valve facing machine including a rotatable grinding means, power means for actuating said grinding means at a predetermined constant speed, a rotatable work carrying spindle positioned relative to said grinding means for maintaining said work in grinding contact with the latter, an electric motor for actuating said spindle, and a manually operable electrical resistance element in circuit with said motor for varying the rotative speed of the spindle relative to the predetermined constant speed of the grinding means at the will of the operator dependent upon the known character and size of the material being ground.

3. A valve facing machine, including a rotatable grinding means, an electric motor for actuating said grinding means at a predetermined constant speed, a rotatable work carrying spindle positioned relative to said grinding means for maintainingsaid work in grinding contact with the latter, an independent electric motor for actuating said spindle, a worm and worm wheel transmission connecting said spindle and last named motor, and a manually controlled rheostat in circuit with the last named motor for varying the rotative speed of the spindle relative to the predetermined constant speed of the grinding means at the will of the operator dependent upon the known character and size of the material being ground.

ERNEST A. HALL. 

